<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>iframe自适应高度</title>
    <script type="text/javascript" language="JavaScript">
        //自动调整iframe框架的方法
        function iframeAuto()
        {
            try
            {
                if(window!=parent)
                {
//定位需要调整的frame框架（在父级窗口中查找）
                    let a = parent.document.getElementsByTagName("IFRAME");
                    for(let i=0; i<a.length; i++)
                    {
                        if(a[i].contentWindow==window)
                        {
                            let h1=0, h2=0;
                            a[i].parentNode.style.height = a[i].offsetHeight +"px";
                            a[i].style.height = "10px";   //首先设置高度为10px,后面会修改
                            if(document.documentElement&&document.documentElement.scrollHeight)
                            {
                                h1=document.documentElement.scrollHeight;
                            }
                            if(document.body) h2=document.body.scrollHeight;
                            let h=Math.max(h1, h2);      //取两者中的最大值
                            if(document.all) {h += 4;}
                            if(window.opera) {h += 1;}
//调整框架的大小
                            a[i].style.height = a[i].parentNode.style.height = h +"px";
                        } } }
            }
            catch (ex){}
        }
        //事件绑定的方法，支持IE5以上版本
        if(window.attachEvent)
        {
            window.attachEvent("onload", iframeAuto);
        }
        else if(window.addEventListener)
        {
            window.addEventListener('load', iframeAuto, false);
        }
        //--> 
    </script>
</head>
<body>
<table border="1" width="200" style="height: 400px; background-color: gray">
    <tr>
        <td>iframe 自适应其加载的网页</td>
    </tr>
</table>
</body>
</html>